Substances containing nitrate and/or nitrite are, for example, domestic waste waters such as those purified in sewage treatment plants. To this end, microorganisms are normally used in sewage treatment plants and initially convert nitrates into nitrites in a stepwise reduction. In another reaction, the nitrites are converted into nitrogen monoxide. The nitrogen monoxide reacts further to form dinitrogen monoxide which is reduced further to nitrogen by using suitable reductases. This process is generally referred to as denitrification.
Dinitrogen monoxide, which is also referred to as laughing gas and is used, for example, as an oxidant for combustion processes, for example, in rocket propulsion systems, or as an anesthetic, is generally manufactured presently by catalytic oxidation of ammonia or thermal decomposition of ammonium nitrate. The manufacture is generally complex with respect to energy and technology.